Putter club

ABSTRACT

A putter club is provided which enables accurate putting by maintaining an angle of a ball-hitting surface with respect to the horizontal plane during a swing. When a player holds a grip with both hands and back-swings from an address position, a shaft is inclined toward a positive side of an X-axis. In this process, the head is pivoted by its own weight around a rotational axis which is horizontal, which is parallel to the ball-hitting surface, and which passes through a center of mass of the head, and an angle of the ball-hitting surface with respect to the horizontal plane is maintained. In the process from start of the swing through an impact to a follow-through, the shaft is inclined toward a negative side of the X-axis. During this process also, the head is pivoted by its own weight around the rotational axis, and the angle of the ball-hitting surface with respect to the horizontal plane is maintained.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a putter club which is used in golf primarily for hitting a golf ball on a green.

2. Related Art

Normally, in putting, an angle of a ball-hitting surface with respect to the horizontal plane at an impact directly affects speed and a distance of travel of a ball. Because of this, in a normal putter club in which a shaft and a head are integrated and fixed, a player adjusts a swing thinking a suitable angle in his mind. In a putter club shown in Patent Literature 1, a rotational support member is interposed between a shaft portion and a grip portion. The player can support the grip portion with one arm and swing the shaft portion in a pendulum-like motion with the other arm, so that fluctuation in the supported grip portion is minimized and the angle is set to a suitable angle.

SUMMARY OF INVENTION Technical Problem

However, in the putting by the normal putter club, the adjustment of the angle by the swing requires a significant expertise. In particular, for a beginner, because the angle changes during the swing the angle, at the impact may become smaller or larger than the original angle, which may result in so-called fat shots or topping balls. In addition, even with the putter club of Patent Literature 1, because the grip portion is supported with one arm, the support point may be easily fluctuated to the swing direction or a direction opposite to the swing direction, which may also result in the fat shots or the topping balls.

The present invention was conceived in view of the above-described circumstances, and an advantage of the present invention is that a putter club is provided which enables accurate putting by maintaining the angle of the ball-hitting surface with respect to the horizontal plane during the swing.

Solution To Problem

In order to solve the above-described problem, the present invention is configured in the following manner. Although reference numerals used in the description of the preferred embodiment to be described later and in the drawings are noted with parenthesis for reference, the constituting elements of the present invention are not limited to those noted elements.

According to one aspect of the present invention described in Claim 1, there is provided a putter club (100) comprising a shaft (110) having a grip (111) to be firmly held by both hands, and a head (130) provided at a front end of the shaft and having a ball-hitting surface (131), wherein the putter club further comprises a head pivoting mechanism (a rotational shaft 124 and a shaft hole 133) which allows the head to be pivoted by a weight of the head with respect to the shaft which is inclined in a vertical plane (XY plane of FIG. 3) by swinging of the putter club, around a rotational axis which is horizontal, which is parallel to the ball-hitting surface, and which passes through a center of mass of the head (a straight line connecting both rotational shafts 124).

According to another aspect of the present invention described in Claim 2, it is preferable that the putter club (100) described in Claim 1 further comprises a lie angle adjusting mechanism (a convex portion 112, a bolt hole 113, a bolt 121, a concave portion 122, and a bolt hole 123) which adjusts a lie angle by rotating the shaft (110) around a second rotational axis (a straight line connecting the bolt hole 113 and the bolt hole 123) which is perpendicular to the ball-hitting surface (131) and fixing the shaft (110).

Advantageous Effects of Invention

According to a putter club described in Claim 1, because the head can be pivoted by the weight of the head with respect to the shaft which is inclined within a vertical plane by the swinging, around the rotational axis which is horizontal, which is parallel to the ball-hitting surface, and which passes through the center of mass of the head, the angle of the ball-hitting surface with respect to the horizontal plane during the swing can be maintained so that the fat shots or topping balls can be prevented and accurate putting is enabled. Moreover, fluctuation of the center of mass of the head in the swing direction or the direction opposite to the swing direction during the swing can be prevented and the swing can be stabilized.

According to a putter club described in Claim 2, a lie angle corresponding to a putting style of the player can be set.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram of a putter club according to a preferred embodiment of the present invention.

FIG. 2 is an assembly diagram showing a structure of a putter club according to a preferred embodiment of the present invention.

FIG. 3 is a diagram showing an operation of a putter club according to a preferred embodiment of the present invention.

FIG. 4 is a diagram showing an operation of a putter club in which a rotational axis is provided external to the head.

FIG. 5 is a perspective diagram of a putter club according to an alternative embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT

A putter club according to a preferred embodiment of the present invention will now be described with reference to the drawings. The putter club according to a preferred embodiment of the present invention is characterized in that the putter club has a head configured to be pivotable around a rotational axis which is parallel to the ball-hitting surface and which passes through the center of mass of the head. A preferred embodiment of the putter club according to the present invention will now be described with reference to FIGS. 1-3.

As shown in FIG. 1, a putter club 100 of the present invention comprises a shaft 110, a fitting member 120 for connecting the shaft 110 and a head 130, and the head 130. A shaft 110 having a circular cylinder shape is made of a material such as steel and carbon, and a certain range of the shaft 110 on an upper end functions as a grip 111 and is covered with a material which can be easily held such as rubber. The head 130 having a rectangular parallelepiped-like shape is primarily made of a metal such as soft iron or alloy stainless, and a front surface of the head 130 becomes a ball-hitting surface 131.

Next, structures and functions of primary portions of the putter club 100 will be described in detail with reference to FIG. 2. A convex portion 112 having a reverse convex shape is formed on a lower end of the shaft 110, the vertices of the tip of the convex portion 112 are smoothed, and the convex portion 112 is machined in a smooth convex spherical shape from the center toward the periphery. Bolt holes 113 which are parallel to an X axis (swing direction) are formed through the convex portion 112 at the center of each side wall of the convex portion.

The fitting member 120 has a mechanism for connecting the shaft 110 and the head 130 and for realizing mutual movement with these members. A concave portion 122 is formed on an upper end of the fitting member 120, and a central bottom portion of the concave portion 122 is machined in a smooth concave spherical shape from the center toward the periphery. In addition, bolt holes 123 which are parallel to the X axis (swing direction) are formed at the center of both side walls forming the concave portion, through the side walls.

In a state where the convex spherical shape of the convex portion 112 is matched with the concave spherical shape of the concave portion 122, the bolt hole 123 on both side walls of the concave portion and the bolt hole 113 of the convex portion 112 are aligned in a straight line, and form a hole of a circular cylinder shape parallel to the X axis. Bolts 121 are inserted from both sides of these holes so that the shaft 110 and the fitting member 120 are connected.

Here, because the concave spherical shape portion of the concave portion 122 and the convex spherical shape portion of the convex portion 112 are slidable with the bolt 121 as a rotational axis, the angle between the shaft 110 and the fitting member 120 can be adjusted to a suitable angle. By tightening the bolts 121 on both ends, the angle can be fixed at that angle. In other words, a lie angle can be adjusted by rotating the head 130 around a straight line passing through the bolt holes 113 and the bolt holes 123 which are perpendicular to the ball-hitting surface 131 and fixing the head 130.

In other words, a lie angle adjusting mechanism for adjusting the lie angle is formed with the convex portion 112, the bolt hole 113, the bolt 121, the concave portion 122, and the bolt hole 123, by rotating the head 130 around a second rotational axis which is perpendicular to the ball-hitting surface and fixing the head 130. With such a configuration, the player can adjust the lie angle to a suitable angle corresponding to the putting style in a state where the bolt 121 is loosened and then fix the lie angle to that angle by tightening the bolt 121.

In addition, a rotational shaft 124 which is parallel to the ball-hitting surface is provided in a projecting manner on a surface, of the fitting member 120, below the concave portion 122, and the other rotational shaft 124 is also similarly provided in a projecting manner on an opposite side on the same circumference over the main body of the fitting member. These rotational shafts 124 are assembled into shaft holes 133 to be described later.

A hole 132 penetrating from an upper surface of the head to the bottom surface of the head is formed in the center portion of the head 130. A center of the hole 132 matches the center of the head 130, and the length of the hole 132 in a Z axis direction (stance direction) which is horizontal and perpendicular to the X axis is slightly longer than a diameter of the fitting member 120 and a length in the X axis direction of approximately ¾ of the head 130. Shaft holes 133 which are parallel to the Z axis are formed in each side wall which is parallel to the X axis forming the hole 132, in communication with the hole 132.

The shaft holes 133 are arranged in a same straight line parallel to the Z axis, and the straight line is placed to pass through the center of mass of the head 130. In addition, the shaft hole 133 has a width and a length for storing the rotational shafts 124. Although not shown in the figures, a guide channel for guiding the rotational shaft 124 to the shaft hole 133 is formed from the bottom surface of the head 130 to the shaft hole 133.

When the fitting member 120 and the head 130 are connected, the rotational shaft 124 is moved from the bottom surface of the head 130 along the guide channel to the shaft hole 133. With this configuration, when the player grips the grip 111 and positions the putter club 100 in place, the uppermost portion of the rotational shaft 124 and the uppermost portion of the shaft hole 133 contact each other, and the weight of the head 130 is supported by the uppermost portion of the rotational shaft 124. In this manner, the head 130 becomes pivotable around the rotational shaft 124 which is parallel to the ball-hitting surface 131 and which passes through the center of mass of the head 130. As shown in FIG. 3 to be described later, the head 130 pivots by the weight of the head during the swing so that the angle of the ball-hitting surface with respect to the horizontal plane is maintained.

That is, a rotational axis which is parallel to the ball-hitting surface 131 and which passes through the center of mass of the head 130 is formed by the straight line connecting the rotational shafts 124. A head pivoting mechanism which allows the head 130 to be pivoted by the weight of the head 130 around the rotational axis during swinging of the putter club 100 is formed by the rotational shaft 124 and the shaft hole 133. After the fitting member 120 and the head 130 are connected, a resin is injected into the guide channel from the bottom surface of the head 130 to the shaft hole 133, to prevent detachment of the head 130 from the fitting member 120.

Next, an operation of the putter club 100 of a preferred embodiment of the present invention will be described with reference to FIG. 3. When the player firmly holds the grip 111 with both hands and back-swings from an address position, the shaft 110 is inclined toward a positive side of X-axis. During this process, the head 130 is pivoted by its own weight, and the angle of the ball-hitting surface 131 with respect to the horizontal plane is maintained.

In the process from the start of the swing through the impact to the follow-through, the angle of the shaft 110 with respect to the horizontal plane is inclined toward a negative side of the X-axis. During this process also, the head 130 is pivoted by its own weight, and the angle of the ball-hitting surface 131 with respect to the horizontal plane is maintained. In other words, during the back-swing, the head 130 is relatively pivoted with respect to the shaft 110 in a counterclockwise direction, and during the swing, the head 130 is relatively pivoted with respect to the shaft 110 in the clockwise direction, so that the angle of the ball-hitting surface with respect to the horizontal plane is maintained. In this manner, the orientation of the head 130 is maintained from the address to the completion of the swing.

By maintaining the angle of the ball-hitting surface 131 with respect to the horizontal plane during the swing in this manner, it is possible to prevent so-called fat shots or topping balls, and to achieve accurate putting. In addition, in order to maintain the angle, it is necessary to prevent instability of the ball-hitting surface by excessive pivoting. In order to do so, a swing which is slow to a certain degree is required from the address to the completion of the swing, which inevitably results in accurate putting.

When the rotational axis is provided external to the head as shown in FIG. 4, the following problem arises.

As shown in FIG. 4, in the back swing, the center of mass of the head does not exist on an extension line of the grip axis, and is shifted to the positive direction of the X-axis, that is, the swing direction. In addition, in the process from the start of the swing through the impact to the follow-through, the constituting elements below the rotational shaft including the head are rotationally moved relatively to the shaft toward the negative direction of the X-axis, that is, in a direction opposite to the swing, in a pendulum-like manner. As a result, the center of mass of the head moves in a direction opposite to the swing, and, in the stage of the follow-through, the center of mass of the head is shifted in the negative direction of the X-axis compared to the extension line of the grip axis, that is, a direction opposite to the swing.

In the case of such a putter club, the player would feel the weight of the head in front of the grip during the back-swing, feel as if the grip overtakes the head during the swing, and feel the weight of the head behind the grip in the follow-through. In other words, the player would experience significant difficulty of hitting because of the change of the relative positional relationship between the grip and the center of mass of the head.

On the other hand, in the putter club 100 of the present embodiment, the rotational shafts 124 are aligned on one straight line which is parallel to the ball-hitting surface 131 and which is horizontal, and the straight line passes through the center of mass of the head 130. The putter club 100 is designed so that the head 130 is pivoted around the straight line as the rotational axis of the head 130. Therefore, as shown in FIG. 3, the relative positional relationship between the grip and the center of mass of the head does not change from the back swing through the impact to the follow-through, and it is easier to hit the ball compared to the putter club as shown in FIG. 4. In particular, in the case of the present embodiment, because a structure is employed in which the rotational axis and the center of mass of the head 130 are placed on an extension line of the grip axis, the player would feel the weight of the head 130 on the extension line of the grip throughout the process from the back-swing through the impact to the follow-through.

As described, with the putter club 100 of the present embodiment, it is possible to prevent fluctuation of the center of mass of the head 130 to the swing direction or a direction opposite to the swing direction during the swing, and to stabilize the swing. In other words, the best position of the rotational shaft is at the center of mass of the head, and a putter club with the rotational shaft closer to the grip as described in Patent Literature 1 results in difficulty in hitting, and, thus, is not suited.

Alternative embodiments of the present invention will now be described.

In the above-described preferred embodiment, an example configuration has been described in which the center of mass of the head 130 is positioned on the extension line of the grip axis as shown in FIG. 3. The present invention, however, is not limited to such a configuration, and the center of mass of the head 130 does not need to be positioned on the extension line of the grip axis, and may be slightly shifted from the extension line. In this case also, because the rotational axis of the head 130 passes through the center of mass of the head 130, the position of the center of mass with respect to the shaft 110 is fixed.

In the above-described preferred embodiment, an example configuration has been described in which the shaft 110 extends from the upper surface of the head 130 in an upward direction as shown in FIG. 1. The present invention, however, is not limited to such a configuration, and the shaft 110 may be connected to the rotational shaft 124 passing through the center of mass of the head 130, and is bent toward the upper direction after being extended from the side surface of the head 130, as shown in FIG. 5.

REFERENCE SIGNS LIST

-   100 PUTTER CLUB -   111 GRIP -   112 CONVEX PORTION -   113 BOLT HOLE -   121 BOLT -   122 CONCAVE PORTION -   123 BOLT HOLE -   124 ROTATIONAL SHAFT -   130 HEAD -   131 BALL-HITTING SURFACE -   133 SHAFT HOLE

CITATION LIST

-   Patent Literature 1: JP Hei 9-192277 A (FIG. 5) 

1. A putter club comprising: a shaft having a grip to be firmly held by both hands; and a head provided at a front end of the shaft and having a ball-hitting surface, wherein the putter club further comprises a head pivoting mechanism which allows the head to be pivoted by a weight of the head with respect to the shaft which is inclined in a vertical plane by swinging of the putter club, around a rotational axis which is horizontal, which is parallel to the ball-hitting surface, and which passes through a center of mass of the head.
 2. The putter club according to claim 1, further comprising: a lie angle adjusting mechanism which adjusts a lie angle by rotating the shaft around a second rotational axis which is perpendicular to the ball-hitting surface and fixing the shaft. 